Decoding circuit for telephone transaction system

ABSTRACT

A system is described for buying materials or services by transferring funds in a bank from the buyer&#39;&#39;s deposit account to the seller&#39;&#39;s account. The transfer of funds is accomplished by means of a &#39;&#39;&#39;&#39;touch-tone&#39;&#39;&#39;&#39; telephone receiving set equipped with a printing means. A computer at the bank receives digital orders from the receiving set, decodes the orders and records the transfer at that location. Each purchaser is provided with a secret purchaser number on a telephone operating card and the entire operation is performed in the presence of the purchaser and a representative of the seller or store.

United States Patent Arnold M. W011 Brooklyn;

John G. Richter, Yonkers, both of, N.Y. 806,439

Mar. 12, 1969 July 20, 1971 Eleetrospaee Corporation Glen Cove, N.Y.

Inventors App]. No. Filed Patented Assignee DECODING CIRCUIT FOR TELEPHONE i/zrzzs Primary Examiner-Benedict V. Safourek Attorney-Albert F. Kronman ABSTRACT: A system is described for buying materials or services by transferring funds in a bank from the buyers deposit account to the sellers account. The transfer of funds is accomplished by means of a touch-tone telephone receiving set equipped with a printing means. A computer at the bank receives digital orders from the receiving set, decodes the orders and records the transfer at that location. Each purchaser is provided with a secret purchaser number on a telephone operating card and the entire operation is performed in the presence of the purchaser and a representative of the seller or store.

DECODING CIRCUIT FOR TELEPHONE TRANSACTION SYSTEM BACKGROUND OF THE INVENTION keeping operations, performing the transaction in a few minutes, and eliminating the possibility of overdrawing funds in the depositor's account.

Modern transactions are now generally accomplished by a check which transfers funds from one bank account to another. This method of doing business is convenient for the purchaser but it takes time and the seller does not actually receive credit for his article sold until several days later. In addition, the banks are now swamped with such a large number of checks that they are required to install special electronic equipment to handle the necessary accounting operations. The bookkeeping operations in the bank have been somewhat simplified by the use of magnetic identifying numbers on the check but it is much easier to eliminate the check entirely and provide for an instant transfer of funds from one account to another.

A computer at the bank is connected to one or more telephone lines and informationreceived from the telephone system controls the computer totransfer funds from one account to another. There are many advantages to this type of system. First the transaction is made in a very short time, less than a minute. Second, the account of the buyer must have funds inexcess of the purchase price, otherwise the purchase cannot be made. This eliminates overdrawn and worthless checks. Third, the seller or the provider of services, knows that his accounthas been increased by a known amount and he can draw on it immediately. This transaction is not subject to delays of mail delivery nor of other delays which may result from mishandling of i the contents of letters and the misinterpretations ofamounts on a check.

A feature of the present invention is a tone decoding circuit and a printing unitwhich may be installed below the usual touch tone receiver set, making the device compact and convenientto handle.

Another feature of the invention is a means for providing the purchaser with a sales' ticket which can be used as a receipt. A carbon copy of the sales ticket is also made by the printing unit for the store. If desired, the carbon copy can be put on a portion of a paper rollwhich includes all the transactions rnade by'this system. i

Still another feature of the invention is to arrange a program I of a time payments for an article purchase. The time payment program can be rejected by the bank and the seller notified by the transmittal of a code number.

Another feature of the invention is an arrangement whereby the buyer can order wholesale 'items'from a factory.

For a better understanding of the present invention, together with other details and features thereof, reference is made to the following description taken in connection with the accompanying drawings.

DESCRIPTION OF THE FIGURES FIG- 1 is an isometric view of the telephone receiver set combined with the tone decoder and printer component.

FIG. 2 is a plan, view of a ticket showing the results of the transaction. This ticket includes the purchaser's name entered by the store clerk, the purchaser's signature and a single line of numbers identifying the purchaser, and recording the transaction.

FIG. 3 is a schematic representation of the component parts of the receiver circuit and including the telephone exchange.

FIG. 4 is a schematic diagram, in block forrn,showing the main components of the system at the bank.

FIG. 5 is a side view, with parts broken away, of the receiver shown in FIG. I. The receiver has been mounted for inductive coupling.

FIGS. 6, 7, and 8, when placed side by side, are a schematic diagram of connections showing the entire circuit of the receiver pickup unit. Three amplifiers and three filter circuits are'shown in block form. Also, the timing and control circuits, and the printing mechanism are shown in block.

FIG. 9 is a schematic diagram of the amplifier-filter circuit shown in block in FIG. 6.

FIG. 10 is a schematic diagram of connections of each of the 16 AND-gates shown in block form in FIG. 6.

FIG. 11 is a schematic diagram of each of the 16 storage multivibrator circuits shown in block form in FIG. 6.

FIG. 12 is a schematic diagram of connections of each of the four multivibrators associated with the diode matrix, in FIG. 7.

FIG. 13 is a side view of the synchronizing wheel shown in FIG. 7.

FIG. 14 is a schematic diagram of the End of Message and Next Line" circuit shown in block form in FIG. 8.

FIG. 15 is a diagram of connections of the Space control circuit shown in block in FIG. 8.

FIG. 16 is a diagram of connections of the print hammer control circuit.

FIG. 17 is a diagram of connections of an alternate form of matrix. 7 7

FIG. 18 is a cross-sectional view of the alternate apertured wheel shown in FIG. 17 taken on line 18-18.

FIG. 19 is a diagram of connections of a photosensitive transducer for use with the apertured wheel shown in FIGS. 17 and 18.

FIG. 20 is a diagram of connections of an additional protective filtering circuit.

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, the receiver circuit includes the usual touch tone receiver unit 10 having digit buttons 11', and control buttons 12 and 13. A-slot '14is provided to receive a punched card for automatic dialing. A start bar 15 is also provided for starting the automatic dialing operation. The two wells 16 at the top of the unit are for storage of punched cards for automatic dialing. In addition to the 10 digits in the touch tone array, a space button 17 is provided as is also an End of Message button 18. The usual receiver-transmitter 24 is a part of the receiver set for normal conversations between two telephone users.

The touch tone unit 10 is placed on a pickup and printing section 21 which includes two depressions or wells 2 and 23 for accommodating the receiver-transmitter unit 24. Section 21 also includes a well 25 where a printing assembly 19 operates to print a card or ticket 26 which is inserted for receiving digits and symbols from a print wheel 27. The print wheel 27 is slidable, mounted on a square shaft 28 and turned by a motor and reduction gear mounted within the printing section container 21. The card is held in printing alignment by a card tray 30, movable in a vertical direction.

On some models the card 26 includes an original data sheet (see FIG. 2) backed with a sheet of carbon paper and a second sheet for receiving a carbon copy of the original. In other models a roll of paper is mounted within the container 21 and all carbon copies are printed on it..lf the roll is used, the store clerk may advance the roll by means of a knurled hand disc 31.

The sales card 26 shown in FIG. 2 is an ordinary data card without holes or embossed surfaces. Most of the data, such as the name of the store and its address, are preprinted on the card. Spaces are reserved for the purchaser's signature and the articles bought. single line is reserved for the printing of digits which identify the purchaser, his social security number,

and the amount of money transferred from one bank account to another. In the card shown in FIG. 2, the name of the store is printed in the upper left-hand corner of the card. To the right of this area is a space for printing the customer's name. An area 32 which includes the entire length of the card is for printing the digits from the computer and from the keyboard keys 11 on the unit 10. A fourth area 33 may be reserved for a description of the article bought, its stock number, the number of places, and the price. Also, there is space 34 for the total and a space 35 for the signature of the purchaser.

FIG. 3 shows the general circuit divisions in the touch tone unit and 21. The card dialing touch-tone telephone 10, 21 is shown connected to an inductive coupled coil 36 positioned immediately under cavity 22 (see FIG. 5). A decoding circuit and a printing unit 37 are also indicated in block form in connection with the telephone receiver. These units are connected to the usual telephone line 38 and a telephone exchange 40 which responds to the switching instructions sent by the computer in the bank. This invention is not concerned with the touch-tone generating system in the receiver, the telephone exchange 40, nor the computer in the bank, these units being well established in the art and well known.

FIG. 4 shows the general layout of the circuits at the bank. The telephone line 41 from the telephone exchange carries information to a data switch control unit 42 which applies the generated tones to a high pass filter 43 and to a low pass filter 44, these filter units being used for the separation of generated tones into two groups and being described generally in several patents, one of which is U.S. Pat. No. 3,076,059, issued .Ian. 29, 1963, to L. A. Meacham et al. The tones passing through the high pass filter 43 are applied to four additional filters 45 and then applied to a decoding network 46. The tones passing through the low pass filter 44 are applied to a similar group of four tonal filters 47 and then applied to the same decoding network 46. The decoding network is connected to the computer storage and arithmetic unit 48 which contains all the depositors accounts and the accounts of all the stores which may sell articles to depositors. The computer storage unit 48 is not a part of this invention and for this reason need not be described in detail. The output of the computer 48 is applied to a conductor 50 which sends its information to circuit 42 and to the telephone line 41 for replying to the request received from the subscriber telephone receiver 10.

FIG. 5 is a side view of the receiver set shown in FIG. 1. In FIG. 5 the receiver-transmitter hand set 24 has been placed in the data receiving position with the sound transducer adjacent to a pickup coil 36 in well 22. In this view some of the details of the printing device are shown.

FIGS. 6, 7 and 8, when placed side-by-side show a schematic diagram of connections of the entire electric circuit but showing many of the circuit elements in block form. This circuit receives coded tonal pulses from the computer, decodes the pulses, and then controls the printing mechanism to print a line of digits on the card 26 in the space 32 to complete the transaction and certify that funds have been transferred at the bank.

Pickup coil 36 may be wound on an iron core 51 for greater efficiency. The coil 36 is connected to the input terminals of an amplifier 52 and the output tenninals of the amplifier are connected to a band-pass filter 39 and then to both the low pass filter 53 and the high pass filter 54. The output of the low pass filter 53 is applied to another amplifier 55 and then sent to a first group of sharply tuned filters 56-1, 56-2, 56-3, and 56-4, each of which is arranged to pass only a narrow band of frequencies. In a similar manner, the output of the high pass filter 54 is applied to an amplifier 57 and then sent to four sharply tuned filters 58-1, 58-2, 58-3, and 58-4, each of which passes only a narrow band of frequencies.

The output pulses from filters 56-58 are applied to 16 AND-gates 60-1 through 60-16, each of these gates having two input connections and operating to deliver an output voltage only when input current pulses are received on both input lines. It is apparent from the circuit of FIG. 6 that each filter circuit 56 is connected to four gates 60-1 through 60-4. Each of the gates 60 will be opened only when a combination of two frequencies are received by the pickup coil 36. These two frequency waves are separated by the filter circuits and then one and only one of the 16 gates 60 is opened. All the gates 60 are supplied with a source of positive and negative voltage shown in FIG. 10, but omitted in FIG. 6. The current supply to gates 60 may be derived from batteries 61 and 62 or from any other convenient power supply. There are times when all the gates are closed. This is accomplished by supplying a voltage pulse over an inhibit conductor 63 from a control circuit (see FIG. 8) designed to protect the circuit from noise and transient disturbances.

Adjacent each gate 60 is a bistable multivibrator forming a series 64-1 through 64-16. Each of these multivibrators, sometimes called flip-flops, has a "set" terminal 65, (see FIG. 11) an output terminal 66, and a reset terminal 67. Each of the set terminals 65 are connected to a gate so that, when the gate is opened, an operating pulse is transferred to the associated flip-flop and its conductance is transferred to the left side, increasing the potential of the output terminal 66 and applying a positive voltage to the output conductor. Each of the 16 output terminals is connected to a conductor which supplies its positive voltage pulse to the printing control circuit or to the space circuit. Another control (see FIG. 14) receives a pulse from one of the multivibrators (64-14) to end the message and normalize the circuits. The operation of these circuits will be described later. Multivibrator 64-1 has its output conductor 68 connected to a space circuit 70 (see FIG. 15) and other control circuits to cause the printing wheel 27 and its associated components to move one space without printing a character.

The digit multivibrators 64-2 through 64-11 are for printing digit characters from I through 9 and 0. The output terminals of these circuits are connected to conductors 74 through 83 which run to a diode matrix (see FIG. 7). Multivibrators 64-12, 64-13, 64-14, and 64-15 control the printing ofa dash a period an asterisk and a dollar sign respectively. The output terminals of these circuits are connected to conductors 85, 86, 87, and 88, all of which run to the diode matrix. Multivibrator 64-16 has two output terminals 72 and 67. Terminal 72 is connected to the collector electrode of the right-hand transistor (see FIG. 11) while terminal 67 is the usual reset terminal. Output terminal 72 is connected by conductor to an end of message circuit 91 shown in detail in FIG. 14. The functions of this circuit 64-16 will be described when the operation of the system is disclosed.

The above described circuits all receive their operating pulses from a pickup coil 36. Other coupling means such as a direct connection to the telephone line or an acoustic coupler may be used. In the latter case, a microphone is connected to the input terminals of amplifier 52.

TIMING MATRIX Synchronism between the decoding circuits and the printing wheel is provided by a diode matrix and a series of four multivibrators, shown in detail in FIG. 12. FIG. 7 shows the diode matrix layout with horizontal conductors connected to the storage multivibrators 64 and the vertical conductors connected to the matrix multivibrators 100, 101, 102, and 103. The latter circuits are connected in series in the same manner as a counting system with a single input terminal 115. Counter impulses are received from a photosensitive transducer 113 which is activated successively by light flashes received from lamp 112 through holes 111 in a wheel turned by shaft 28 which also supports the printing wheel 27. Wheel 110 (see FIG. 13) contains 16 holes, 15 of which are spaced so as to transmit light from lamp 112 and one hole 108 closer to the center of rotation for passing light from lamp 107 to activate a second photosensitive transducer 105.

Light flashes from lamp 112 are transformed into electrical pulses by transducer 113, amplified by transistor 114 and then a negative pulse is applied to the input terminal 115 over conductor 116 to transfer conductance from the right-hand transistor 103A to the left-hand transistor 1033 (see FIG. 12). When a second pulse is received conductance is transferred back to transistor 103A and, at the same time, a triggering negative pulse is sent from the output terminal of circuit 103 to circuit 102 over conductor 117. Circuit 102 is identical to circuit 103 and conductance of its transistors is transferred in a similar manner. During the second activation of circuit 102, a pulse is sent to circuit 101 and after actuating pulses from transistor 114, all the multivibrators are conductive on their left side. The 16th pulse, from transistor 106 over conductor 104 is applied to all the reset terminals 118 and all the circuits are normalized, ready for another printing cycle.

The above described counting" operation applies a series of voltages to the vertical conductors in the matrix (see FIG. 7). When conductance is on the right side, terminal 1 is at a low voltage and terminal 0 is at high voltage (+13 volts). A low voltage applied to a vertical conductor results in no conductance through any of the diodes 120 cross connected between the vertical conductor and the connected horizontal conductor. in a complete series of counts" resulting from a single turn of wheel 110 there are 16 combinations of applied voltages given to the vertical conductors, thereby providing 16 timed pulses sent over conductor 84 to the base electrode of transistor 121 through blocking capacitor 122. The printing pulse is amplified by transistor 123 and then sent through diode 124, a capacitor 125 to transistor 126 and to the base electrode of transistor 127A by means of diode 128 and capacitor 130. Circuit 127 is for timing the printing action and allows for the inductance of a printing solenoid 131, and the inertia of a printing hammer 132. The timing action can be made adjustable by varying one of the resistors 133. A printing control pulse is sent through diode 134 and over conductor 135 to the print control circuit 136. At the same time a portion of the same pulse is sent through diode 137 and over conductor 138 to the space circuit 70. The printing control circuit operates solenoid 131 and hammer 132 to print a desired character on the card in the printing assembly 19. The space circuit 70 sends an operating pulse over conductor 140 winding 141 and armature 142 to operate an escapement pawl 143 and permit spring 144 to pull the printing assembly 19 one character space to the right to be ready for' the next printing operation. 7

It should be noted that all the horizontal conductors in the matrix (see FIG. 7) are connected through resistors 145 to a common supply line 146 which is connected to conductor 147 and the positive terminal of the power supply 61. When the horizontal conductors in the matrix 74 are not actuated by signals coming from the multivibrators 64-1 through 64-16, they are maintained at ground potential. When any one of the multivibrators is actuated, the horizontal conductor connected to it is given a positive potential. The voltage is transmitted to conductor 84 but no direct current flows through the conductor because of blocking capacitor 122.

The operation of the diode matrix in connection with the circuits is as follows: Let it first be assumed that all the circuits have been reset by the beam of light from lamp 107 through hole 108. All four multivibrators are now conducting on the right side and current flows through all the vertical conductors except the first 150 and the fifth 154. However, there is no current pulse sent through any of the diodes 148 to conductor 84 because there is sufl'lcient current drain through at least one of the cross connected diodes 120 to maintain all horizontal conductors at a low potential. For example, conductor 74 is connected through diode l-A to the 1 terminal in circuit 103 which is at low potential. Conductor 75 is connected by diode 120-B to the t terminal incircuit 102 and conductor 76 is connected by diode 120-C to terminal 1 in circuit 103. All the other horizontal conductors are connected in a similar manner.

Now let it be assumed that the wheel 110 moves three of its holes past lamp 112 and then permits light to shine through the fourth hole 111. The four pulses applied to the four multivibrator circuits have switched conduction four times leaving conduction in circuit 103 on the right side. The two pulses from circuit 103 have switched conduction of circuit 102 twice leaving conduction on the right side. The single pulse from circuit 102 have switched conduction of circuit 101 once, leaving it on the left side. All the multivibrators are the same as before except circuit 101 has its 0 terminal at low voltage and its 1 terminal at high voltage. All the horizontal conductors are connected to low voltage terminals except conductor 77 (for printing a 4). The only two diodes -D and 120-5 are connected to high voltage terminals, there is no current drain, and when a positive current pulse is applied from storage multivibrator 64-5, it continues through diode 148 to conductor 84, the printing timing circuit 127, the print control circuit 136, and solenoid 131 to actuate hammer 132 to strike the 4 character on the print wheel 27 and print that numeral on the card 26.

CARD TRAY AND MOTOR CONTROLS As mentioned above, the system is started by placing a card 26 in its tray or holder 30 and then depressing a start button (See FIG. 8). This action operates a pawl 161 releasing a one-revolution clutch 162 which turns and pulls a cord 163 to lower the card tray to a printing position. At the same time, contacts 164 and 165 under the start button are closed and contacts 166 under the card tray are closed. Contacts 164 start an alternating current motor 167 by completing a circuit which may be traced from the power plug 168, over conductor 170, to the motor 167, then through contacts 164 under the start button 160, then over conductor 171, and back to the other terminal on the power plug. This circuit starts the motor 167.

When contacts 166 under the card tray 30 are closed, a circuit is completedwhich may be traced from the positive terminal of a source of direct current power 172, over conductor 173, through contacts 166 and a limiting resistor, to the winding 174 of a relay, to ground and the negative terminal of source 172. This action operates the relay, closes four pairs of contacts and opens one pair. The closure of contacts 95 completes a supply circuit which can be traced from the positive terminalof the source of potential 172, over conductor 173, through contacts 95, then over conductors 96 and 176, through resistor 175 to the space magnet winding 141, and then to the space circuit 70. Conductor 96 is also connected to the End of Message" circuit 91 and (see FIG. 14) the anodes of two silicon controlled rectifiers 93 and 257.

In order'to tell the operator that the system is ready for a printing operation, a ready lamp 177 is provided. This lamp lights only when the relay is in its operated condition and contacts 178 areclosed. The lamp 177 and contacts 178 are connected in series with a secondary winding 180 of a transformer whose primary'winding 181 is connected to the power lines in series wit a main power switch 182. Lamp 177 is in parallel with a diode 183 and a capacitor 184. During the operation of the circuit, capacitor 184 is charged to a direct current potential but the complete" lamp 185 cannot pass current because contacts 186 are open. At the completion of the printing cycle when the relay is normalized and contacts 186 are closed, lamp 185 is lighted because a series connected silicon controlled rectifier 187 is maintained conductive by the charge on capacitor 184. As soon as the charge leaks off, the rectifier is made nonconductive and the lamp is extinguished.

A third pair of contacts 188 is connected directly across the start contacts 164 but in series with the motor 167 Closure of contacts 188 insures that the motor 167 will continue to run as long as the relay is actuated-A fourth set of contacts 190 connects the direct current source of potential 172 to the two lamps 107 and 112. As long as the relay is operated, the lamps adjacent to the wheel 110 remain lighted and provide light flashes for transducers 105 and 113.

INPUT NOISE CONTROL CIRCUITS It should be noted that most of the printing signals come from the computer at a bank which may be situated some distance from the receiver set. The telephone lines carrying the printing signals are often subjected to inductive noise which may result from switching transients, adjacent phone conversations and power line currents. It has been found that these noise sources are either of short duration or, if sustained, the frequency is varied. In order to protect the printing circuit from these unwanted signals, a time-filter circuit is employed. This circuit monitors the incoming signals by first passing the positive signal currents through two diodes, AND-gates, and then amplifying the combination currents and charging a capacitor by the rectified currents until a desired voltage is obtained. Then, after a short delay, during which the AND-gates 60 are inhibited, the signals are sent to the printing circuit.

The control circuit which monitors the input signals is shown at the bottom of FIGS. 6, 7, and 8 and includes input conductors 191 and 192 connected between amplifiers 55 and 57 and two AND-gates gate diodes 193 and 194. The output of the AND-circuit is connected to a transistor 195 which is arranged to send an output series of pulses through capacitor 196 to transistor 197. Capacitor 198 charges up almost immediately and retains a minimum DC voltage level during the signal interval. The voltage in capacitor 198 is applied to conductor 200 and the base electrode of the first transistor 201 in the Schmitt trigger circuit shown in FIG. 7. The DC voltage on capacitor 198 is present only during the time when both input signals are received. The Schmitt trigger circuit is now activated and a positive output pulse is sent through capacitor 203 to trigger a bistable multivibrator circuit 204, making transistor conductive and transistor 206 nonconductive. This sends a positive pulse to transistor 207 which applies a positive voltage to conductor 208 and charges capacitor 210 through a variable resistor 211 in series with a diode 209. As before, the voltage on capacitor 210 builds up slowly and, after a time delay of about 20 milliseconds, a second Schmitt trigger circuit 213 is activated, sending a positive pulse through diode 214 and over conductor 215 to normalize the bistable multivibrator circuit 204. At the same time the circuit 204 is normalized, a pulse is sent from the collector of transistor 205 over conductor 216 to make transistor 217 conductive and discharge capacitor 210.

The operating pulse from the second Schmitt trigger 213 also moves through capacitor 218 (see FIG. 8) to trigger a monostable multivibrator circuit 212 to send a negative pulse from transistor 212A to transistor 219. The emitter voltage of transistor 219 then moves to ground potential and sends a pulse over conductor 63 to all the AND-gates 60 (see FIG. 6). This pulse enables the AND-gates and permits them to pass any operating signal from the filter-amplifiers 56 to the storage multivibrators 64.

Diodes 219A, 124, and 124A form a triple AND-gate. When the monostable multivibrator circuit 212 returns to its normal state, a positive pulse is applied to transistor 219 and its emitter assumes a positive potential. Conduction of a voltage pulse through this AND-gate (diodes 219A, 124, and 124A) then through capacitor 125 to the base of transistor 126, occurs only when positive pulse coincidence exists on conductor 84, conductor 163, and the collector of transistor 125A. The AND-gate output pulse is inverted, passing through transistor 126 and then a negative pulse is sent through diode 128 and capacitor 130 to the print timing monostable multivibrator circuit 127. This circuit transfers conductance from transistor 127A to 1278 for a printing time interval which can be adjusted by changing resistor 133. The positive output pulse is sent through diode 134 to the print control circuit 136 and through diode 137 to the space control circuit 70.

PRINT CONTROL CIRCUIT The print control circuit 136 is shown in block in FIG. 8 and in detail in FIG. 16. The timed printing signal is received over conductor 135 and is applied totwo transistors 220 and 221, coupled together to form a high impedance Darlington circuit. The output of this combination is applied to an amplifier transistor 222, the collector of which is connected to conductor 223 and the print solenoid 131 (see FIG. 8). The return conductor 224 is connected to the 50 volt supply line (FIG. 16) in parallel with a diode 225 for bypassing inductive transients generated by coil 131.

The print hammer 132 (FIG. 8) is operated once each printing cycle except when a space is called for. During this time the printing input circuit is short circuited to ground by a transistor 226 (FIG. 16) having its emitter connected to ground, its base connected through part of a voltage divider to conductor 68 and the top storage multivibrator 64-1 which is activated each time a space is desired. The pulse sent over conductor 68 is applied to the base of transistor 226 making it conductive and short circuiting the input terminals of the printing circuit.

SPACE CONTROL CIRCUIT The space control circuit 70 is shown in detail in FIG. 15. The input to this circuit includes two transistors 227 and 228 coupled together to form a high impedance Darlington circuit, similar to transistors 220 and 221 in the print circuit. The space signal is received over conductor 138 (when a character is printed) and is applied to the base of transistor 227. The result is an output pulse sent over conductor 140 to the space magnet 141 which actuates armature 142 and escapement pawl 143 to move the printing assembly one space. A space operation must be made each time a character is printed and for this reason the output pulse of transistor 127A is divided into two portions, one sent over conductor 135 to the print circuit 136 and the other sent over conductor 138 to the space circuit 70.

When a space operation is desired without printing a character, AND-gate 60-1 is opened and storage multivibrator 64-1 is activated, thereby sending a signal to the diode matrix over conductor 235. At the start of the printing cycle, when the matrix multivibrators are normalized, the first vertical conductor 150 and the fifth vertical conductor 154 are provided with positive voltages so that the cross connected diodes to conductor 235 do not short out the signal pulse from circuit 64-1 and, at this time, the signal pulse is transmitted through diode 148, then over conductor 84 to transistor 121 (FIG. 8). The pulse is amplified, as described above, by transistors 123 and 126 and then sent through diode 128 and capacitor 130 to the printing monostablemultivibrator 127 to produce the same type of printing and spacing operation as described previously. However, there is no printing operation, this action being eliminated by the following circuit.

When the storage multivibrator 64-1 (FIG. 6) is activated, a second pulse is sent from terminal 72, over conductor 68 to the printing control circuit 136 (FIG. 8). Referring now to the detail circuitry shown in FIG. 16, the pulse received over conductor 68 makes transistor 226 conductive and the printing signal received over conductor is short circuited to ground so that no pulse is sent over conductor 223 to solenoid 131.

A short time interval after the space circuit (FIG. 15) is activated and sends a signal over conductor 140 to move the printing assembly 19, a pulse is transmitted over a delay circuit including capacitor 236 and resistor 237. This pulse builds up slowly and, after a few milliseconds, changes the voltage on the base electrode of transistor 238 to make it conductive and send a reset pulse over conductor 240 to all the storage multivibrators 64 (FIG. 6) and reset or normalize the one which has been actuated. This action completes the space operation. It should be noted that the normalizing or reset operation occurs at the end of each spacing and printing operation.

END OF MESSAGE CIRCUIT The de re sant the START button 160 (FIG. s), as noted above, activates all the operating circuits to print the desired characters. One of the results of the start operation is the activation and latching of the relay having winding 174. Another is the start of motor 167 and the sequential activation of the matrix multivibrators 100, 101, 102, and 103. When the message is complete,.these operations and others must be terminated and their circuits normalized. The end of the message is terminated by a signal which includes two frequencies each passing through filter circuit 56-4 and filter circuit 58-2, respectively; These signals then pass through AND-gate 6044. activate storage multivibrator 6444 and a positive pulse is thereby sent over conductor 87 through the diode matrix fortiming. The timed pulse is then transferred by conductor to the print circuit as explained above in connection with the description of the printing control 136.

A-portion of the pulse from circuit 64-14 is sent over conductor 241, (FIGS. 7 and 8) to the end of message circuit 91. Details of this circuit are shown in FIG. 14 where input conductor 241 is connected to the base of transistor 89, with the emitter coupled to the firing electrode of a controlled rectifier 93. This'rectifier has its anode connected to a common supply conductor 96 which is connected to the positive terminal of battery 172 in. series with relay contacts 95. The cathode of rectifier 93 .is connected by conductor 97 to a magnet 242 which operates an armature 243 and. pulls two cords244 and 245. The first cord 244 operates a pawl 246 and trips a one revolutionclutch 247: to pull another cord .248 which passes over pulley 250 and moves the printing assembly 19 back to its original starting position. The second cord 245 moves a ratchet pawl 251 out of engagement with teeth on the card tray. 30 and aspring 252 pulls the card tray up to its loading position and, at thc same time, releasing the card.

. There may be times when the operator at the bank; sends a message which is too long for the capacity of the card. In this theprinting assembly is advanced to the right until the tlimitis reachedand a pair of limit contacts 253 are closed.

These contacts complete afcircuit which may be traced-from the positive l3 volt supply line 147 (FIG. 8) over conductor 147A to the contacts 253, then over conductor 254, through a blocking capacitor 255 to the controlled rectifier 93. This action again terminates the printing action as described above. A manual switch 256 is also provided so that the operator in the store may stop the printing action'and normalize the circuits. The-switch contacts are connected in parallel across contacts 253s" There are provisions in the circuit shown for a next line" operation. This is not always necessary and for many banking transfer of funds, a single line of characters, as shown in FIG. 2, is sufficient. When a second line of characters is desired, a

, signal composed of two frequency components is sent to the amplifier-filter circuits, filters 56-2'and 58-4 send signals to AND-circuit 60-l6and an output signal is sent over conductor 90 to the. end of message" circuit 91 (FIGS. 8 and 14). Conductor90 is coupled to the base of transistor 92 and, when activated, the emitter electrode sends a pulse through a blocking capacitor to the firing electrode of a second controlled rectifier 257 having its anode coupled to conductor 96 and the power supply and its cathode connected to conductor 258which leads directly to'magnet 260 (FIG. 8). When current is received by magnet 260, its armature 261 is moved upward and cords 262 and 263 are pulled, thereby unlatching pawls 264 and 246 to release one revolution clutches 247 and .265. Clutch 247 pullsthe print assembly to the left as before to start the next line and clutch 2'65 pulls the card tray to a new location so that the next line can be printed on a blank portion of the card.

At the end of the end of message" operation when controlled rectifier 257 is madeconductive, the voltage drop across resistor 266 (FIG. 14) causes a voltage pulse to be sent over conductor 267 to the reset terminal 67 on storage multivibrator 64-16. The other storage multivibrators are reset after each space operation by a voltage sentfrom the space circuit overconductor 240.

The holding circuit which holds the relay in its activated condition during the printing operations is in series with the pair of contacts 166 which were closed by the card tray being lowered into printing position. At the end of the printing 1 operation, when armature 243 is operated, the card tray is released and is moved to its unloaded position, opening contacts 166 and thereby breaking the holding circuit. The relay is normalized, contacts 190, 95, 178, and 188 are opened and contacts 186 areclosed. Contacts 186, as described previously, complete a circuit through indicator lamp 185 and controlled rectifier 187 to show a COMPLETE signal on the panel of container 21 (FIG. 1 The lamp 185 is lighted for approximately seconds and then its current is cut off automatically when capacitor 184 is discharged. 7

The detailed circuits shown in FIGS. 9, 10, 11, and 12, indicate the actual wiring of these units as employed in a workable system. There are many variations of these units which may be used and the invention is" not dependent upon the details of: construction as shown. FIG. 9 shows a commercial integrated amplifier 270 used in conjunction with a double T to increase the current amplitude.

- The'AND-gate 60, shown in FIG. 10, is only one of many similar circuits which can beused to select the proper combination tonal signal frequencies and transfer an output signal to the associated storage multivibrators 64. The construction of this AND-circuit 60 is based on the requirement of an enable signal applied over conductor 63 which opens the gate to permit an output signal to-pass through after transistor 219 is activated by the two-tone signal.

FIGS. 11 and 12 show the details of two bistable multivibrators, each including two transistors. The storage multivibrator 64 is a simplified design because it is activated by a signal applied to terminal65, to produce a positive output level at terminal 66, then reset to ground potential by a negative pulse applied to terminal 67. No other action is necessary. The multivibrator shown in FIG. 12 is more complicated because the activating or'triggering pulse applied to terminal must transfer conductance from one transistor to the other a number of times during a printing operation. The action must be fast since the transfer of conductance must occur during the time one character on printing wheel 27 is replaced by the next character. In order to speed the action, capacitors 273 and 274 have been added. These capacitors, however, are not large enough to produce a free running generator. Variations of this circuit can be used for this operation.

FILTER INHIBITOR CIRCUIT The enable circuit in each AND-gate is intended to restrict the gateaction to a limited time interval. The inhibiting action also eliminates unwanted actuating signalswhich are due to noise on the line betweenthe store and the bank. As an added precaution, an additional inhibit circuit 275 has been added to disable six of the eight filter circuits 56 to prevent self print cut of characters when the bank terminal is dialed. This circuit (FIG. 6) is a bistable multivibrator including two transistors 276 and 277 and the usual crossconnections between bases and collectors. The voltage signal is derived from the collector electrode of transistor 277 and is amplified by transistors 278 and 280. The output of the last transistor 280'is applied to the positive voltage terminals 281 (see FIG. 9) in series with a small resistor (10 ohms). An additional RC circuit is conthe start button is depressed. The start button 160 closes two pairs of contacts 164 and 165. Contacts 165 complete a circuit which may be traced from the negative terminal of the power supply 62, over conductors 283 and 284 to the switch contacts 165. From there the circuit continues over conductors 285 and 286 to the base of transistor 277, transferring conductance to transistor 276 and applying a zero or ground potential to conductor 282 to cut off the operation of the connected filter circuits 56.

When the bank computer begins transmission, a "start of message" signal is received by filters F-1 and F-8 activating gate 60-13 and its associated storage multivibrator 64-13. This signal passes through the matrix and a character is printed by the print mechanism. At the same time, a positive pulse appears on conductor 287, reversing the previous condition of the bistable multivibrator 275. A positive voltage is then applied to conductor 282, supplying an operating voltage to the six connected filter circuits 56.

An alternate form of diode matrix is shown in FIG. 17. This simplified circuit can only be used when 15 successive pulses are applied to the vertical matrix conductors in timed relationship with the printing wheel. In FIG. 17, the operating pulses are supplied by 15 photosensitive transducer circuits 300 secured to a cup shaped stator 301 having l5 holes 302 formed in its flange portion 303. The circuits are equally spaced around the flange except for one blank portion. Cooperating with stator 301 is a rotor 304, also cup shaped and having a flange 305 which fits closely inside the flange 303 of the stator. The flange 305 is provided with a single hole 306, in the same rotary plane as holes 302. Rotor 304 is secured to shaft 28 (see FIGS. 7 and 8) which also carries the print wheel 27 and is turned by motor 167. It is obvious that rotor 304 provides the same function as the apertured wheel 110 shown in FIG. 7.

A lamp 307 is placed in axial alignment with the shaft 28 and in the plane of the holes 302. As the rotor 304 turns, light flashes pass through the rotor hole 306 and the stator holes 302, thereby providing successive light pulses to all the IS photosensitive circuits.

Each of the photosensitive circuits 300 (see FIG. 19) includes a photosensitive transducer 308 which in this case is a semiconductor unit although other photosensitive transducers can be used. The transducer 308 is connected to a battery 310 which sends current through the collector and emitter electrodes only when light is incident on the semiconductor surface. Transducer 308 is direct coupled to a transistor 311 which is biased by a voltage divider to be normally nonconductive. When lightactivates transducer 308, it conducts and alters the bias on transistor 311 to make it conductive.

When no current flows from battery 310 through resistor 312, the potential of output conductor 313 is at ground potential. When the transistor conducts, current flows through resistor 312 and its voltage drop raises the potential of conductor 313 to a definite positive value. The result is a positive pulse applied over conductor 313 every time a light flash is applied to transducer 308 The operation of the matrix circuit is as follows: When light is not incident on a transducer 308, the potential of all the vertical conductors 313 is at zero or ground potential. All the horizontal conductors in the matrix are connected to a positive potential source by way of conductor 146 (see similar connection in FIG. 7) and resistors 145. However, a positive pulse applied to any of the horizontal conductors cannot be transmitted to conductor 84 because all horizontal conductors are effectively grounded through diodes 120. When a light flash is incident on any of transducers 308, its associated vertical conductor is made positive, but there is still no output pulse sent over conductor 84 because of the blocking action of diode 120.

If a positive pulse is applied to one of the horizontal conductors at the same time a positive potential is applied to a vertical conductor, then a positive pulse will be sent through one of the isolating diodes 148 to conductor 84 and the printing mechanism. The hole 306 in the rotor is synchronized with the print wheel so that a positive potential on any one of the horizontal conductors results in the printing of a character identified with that conductor.

The circuit shown in FIG. 20 is another control circuit which can be omitted from the general system but its use can eliminate false starts and recordingerrors. Its main purpose is to prevent the computer from accepting data signals from the subscriber set when a data card is not properly placed in the card tray. As soon as the card is properly placed, a two-tone signal is sent to the computer, unlocking its input circuit.

The circuit includes two oscillators 320 and 321, each tuned to a definite frequency by a double bridge type filter. Each oscillator includes two transistors 322 and 323 and a filter combination 324 which determines the frequency of oscillation. Feedback connection from the filter 324 to the base electrode of transistor 322 is made by conductor 325. The circuits start to oscillate when the collector supply connector 326 is connected to a l 3 volt supply. As shown in FIG. 20, a start" switch and a card lock switch 327 must both be closed before the oscillators can function. When the card is properly placed and the start button depressed, two alternating currents of differing frequencies are generated by oscillators 320 and 321 and combined by output conductors 328 and 330. The combination signals are amplified by transistors 331 and applied to the telephone line and the bank's computer by a transfonner 332. The transformer terminals 333 may be connected directly to the telephone line or they may be coupled inductively or acoustically to one of the elements of the subscriber hand set in order to send both currents to the computer. A receiving set, similar to circuits 56 and 60 (see FIG. 6), receives the signals and, if the frequencies are correct and if they occur at the same time, the computer is controlled to start sending data to the printing assembly under the subscriber set.

Having thus fully described the invention, what We claim as new and desired to be secured by Letters Patent of the United States, is:

1. A decoding circuit for receiving selected pairs of alternating currents having distinctive frequencies and for delivering a current pulse to a load circuit timed in accordance with its decoded valves comprising:

a. a plurality of electrical band-pass filtering circuits, each for sensing a designated current frequency and for passing an output pulse whenever the designated frequency current is applied;

. a plurality of AND-circuits each having two inputs and a single output circuit, each of the input circuits connected respectively to a filtering output circuit, and each AND- circuit having an output terminal connected to a load, each of said AND-circuits delivering an output pulse to its load circuit only when both input circuits receive current pulses;

c. a plurality of bistable multivibrator storage circuits, each having their input circuit connected to an AND-output terminal, each of said storage circuits adapted to a activated by the AND-circuit to apply a voltage to an output terminal to indicate a decoded symbol;

a diode matrix including a plurality of input conductors each connected to an output terminal of a storage multivibrator, a plurality of bias conductors for sequentially applying bias voltages to the matrix, a single output conductor connected to all the input conductors in series with a plurality of barrier diodes, and a plurality of crossconnected diodes connected between the input conductors and the bias conductors for selectively energizing a predetermined input conductor during a cycle of operations;

e. and a plurality of energizing circuits connected to the bias conductors for sequentially applying bias voltages thereto, said energizing circuits controlled by a means for producing synchronizing pulses in timed relation to a utilization circuit.

minal, and a second amplifier stage in series with the first for delivering a current pulse to an output terminal when a voltage having a desired frequency is applied to the input terminals of the first amplifier.

3. A decoding circuit as claimed in claim 1 wherein each of said AND-circuits includes a first and second input terminal each connected to a common junction point in series with a capacitor and a diode, a source of positive potential in series with a resistor connected to each capacitor, said common junction point connected to an output terminal in series with a diode.

4. A decoding circuit as claimed in claim 3 wherein an enable circuit is connected to said common junction point, said enable circuit connected to a source of negative potential for removing an inhibit voltage supplied to the junction point for disabling the AND-circuit so that no output signal is permitted.

5 A decoding circuit as claimed in claim 4 wherein said inhibit circuit is connected to all the AND-circuits for disabling all of them after a desired multivibrator storage circuit has been activated.

6. A decoding circuit as claimed in claim 1 wherein said bistable storage circuits each include two transistors, each having a base electrode connected to a collector electrode in the other transistor, said multivibrator storage circuits each having an input terminal connected to a base electrode in one of the transistors for transferring conductance from one transistor to the other, and' a reset terminal connected to a common conductor which applies areset pulse from a control circuit to reset all the storage circuits which may-have been activated.

7. A decoding circuit as claimed in claim 1 wherein said diode matrix includes a means for supplying a voltage to each of said input conductors, said means including a plurality of resistors each connected respectively between one of the input conductors and a source of potential.

8. A decoding circuit as claimed in claim 1 wherein the energizing circuits connected to the bias conductors include a plurality of bistable multivibrators connected in series for sequential actuation, each of said multivibrators having a single input terminal coupled to two transistors whereby successive'applications of a voltage pulse transfers conduction from one transistor to the other.

9. A decoding circuit as claimed in claim 8 wherein a photosensitive transducer is coupled to the energizing circuits for supplying the synchronizing pulses, a lamp is mounted adjacent to the transducer for supplying light thereto, and an apertured rotatable wheel is positioned between the lamp and the transducer for sequentially delivering light pulses to the transducer.

10. A decoding circuit as claimed in claim 9 wherein a second photosensitive transducer is coupled to a reset terminal on each of the energizing circuits for normalizing the energizing circuits after a cycle of operations, said second transducer mounted adjacent to the rotatable wheel for receiving a light pulse once during each revolution.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,59 ,5 3 Dated July 20, 1971 Arnold M. wolf, et a1 Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 12, line 44, "valves" should read values Signed and sealed this 17th day of October 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GO'I'TSCHALK Commissioner of Patents Attesting Officer FORM F'O-1050 (10-69) USCOMM DC uo376.pg r us. covnmnnn rnnmna ornce: no u-su-s.u, 

1. A decoding circuit for receiving selected pairs of alternating currents having distinctive frequencies and for delivering a current pulse to a load circuit timed in accordance with its decoded valves comprising: a. a plurality of electrical band-pass filtering circuits, each for sensing a designated current frequency and for passing an output pulse whenever the designated frequency current is applied; b. a plurality of AND-circuits each having two inputs and a single output circuit, each of the input circuits connected respectively to a filtering output circuit, and each ANDcircuit having an output terminal connected to a load, each of said AND-circuits delivering an output pulse to its load circuit only when both input circuits receive current pulses; c. a plurality of bistable multivibrator storage circuits, each having their input circuit connected to an AND-output terminal, each of said storage circuits adapted to a activated by the AND-circuit to apply a voltage to an output terminal to indicate a decoded symbol; d. a diode matrix including a plurality of input conductors each connected to an output terminal of a storage multivibrator, a plurality of bias conductors for sequentially applying bias voltages to the matrix, a single output conductor connected to all the input conductors in series with a plurality of barrier diodes, and a plurality of cross-connected diodes connected between the input conductors and the bias conductors for selectively energizing a predetermined input conductor during a cycle of operations; e. and a plurality of energizing circuits connected to the bias conductors for sequentially applying bias voltages thereto, said energizing circuits controlled by a means for producing synchronizing pulses in timed relation to a utilization circuit.
 2. A decoding circuit as claimed in claim 1 wherein said electrical filtering circuits each includes a double T filter including a first amplifier stage, a series voltage divider circuit having a capacitor connected between the midpoint of the divider and an output terminal, two capacitors connected in series across the voltage divider with a resistor connected between the junction of the capacitors and the output terminal, and a second amplifier stage in series with the first for delivering a current pulse to an output terminal when a voltage having a desired frequency is applied to the input terminals of the first amplifier.
 3. A decOding circuit as claimed in claim 1 wherein each of said AND-circuits includes a first and second input terminal each connected to a common junction point in series with a capacitor and a diode, a source of positive potential in series with a resistor connected to each capacitor, said common junction point connected to an output terminal in series with a diode.
 4. A decoding circuit as claimed in claim 3 wherein an enable circuit is connected to said common junction point, said enable circuit connected to a source of negative potential for removing an inhibit voltage supplied to the junction point for disabling the AND-circuit so that no output signal is permitted.
 5. A decoding circuit as claimed in claim 4 wherein said inhibit circuit is connected to all the AND-circuits for disabling all of them after a desired multivibrator storage circuit has been activated.
 6. A decoding circuit as claimed in claim 1 wherein said bistable storage circuits each include two transistors, each having a base electrode connected to a collector electrode in the other transistor, said multivibrator storage circuits each having an input terminal connected to a base electrode in one of the transistors for transferring conductance from one transistor to the other, and a reset terminal connected to a common conductor which applies a reset pulse from a control circuit to reset all the storage circuits which may have been activated.
 7. A decoding circuit as claimed in claim 1 wherein said diode matrix includes a means for supplying a voltage to each of said input conductors, said means including a plurality of resistors each connected respectively between one of the input conductors and a source of potential.
 8. A decoding circuit as claimed in claim 1 wherein the energizing circuits connected to the bias conductors include a plurality of bistable multivibrators connected in series for sequential actuation, each of said multivibrators having a single input terminal coupled to two transistors whereby successive applications of a voltage pulse transfers conduction from one transistor to the other.
 9. A decoding circuit as claimed in claim 8 wherein a photosensitive transducer is coupled to the energizing circuits for supplying the synchronizing pulses, a lamp is mounted adjacent to the transducer for supplying light thereto, and an apertured rotatable wheel is positioned between the lamp and the transducer for sequentially delivering light pulses to the transducer.
 10. A decoding circuit as claimed in claim 9 wherein a second photosensitive transducer is coupled to a reset terminal on each of the energizing circuits for normalizing the energizing circuits after a cycle of operations, said second transducer mounted adjacent to the rotatable wheel for receiving a light pulse once during each revolution. 